Melafix is for bacterial infection, Pimafix is for Fungal infection.

I think of Melafix and Pima fix as antiseptics...wound healers, infection preventers?
I've had sucess in ripped or torn fins, wounds, sores being healed without fungus or infection appearing.
I haven't had much success when using it for a really bad bout of fin rot.  I HAVE had success in using Melafix when I've had a really bad bout of fin rot AND using antibiotics also.   I think the tea treen oil is soothing and I am currently using it along with heat and salt for ich.  Ich makes holes in the fish and this can lead to infection.  With the Melafix and the Pimafix in the tank while my fish have ich, I have seen releif from the iching and flashing.  The fish just looked miserable before now they look spotty but not so irritated.

Already everything covered about Melafix and Pimafix from API.
Just to emphazise: Melafix: All natural antibacterial remedy for the mamagement of aquarium fish deseases: aids healing of damaged fins and open wounds, use when introducing new fish to the aquarium.
Pimafix: All natural antifungalremedy for the treatment of aquarium fish deseases. Rapidly treats fungal infections on body and fins. Also treats internal and external bacterial infections.
This is whats printed on the labels. I always keep it, like I keep painkillers in our little "home pharmacy"
So in case sth happens, this is the first thiny I use and most times it is sufficient, as I watch our fishies every single day.

Melafix can be used for african dwarf frogs apparantly as well. I got advised it for my sick frog...unfortunately he was too ill and didn't make it